organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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N,N,N′,N′-Tetra­methyl-N′′-[2-(N′,N′,N′′,N′′-tetra­methyl­guanidino)eth­yl]guanidine

aInstitut für Organische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany, and bFakultät Chemie/Organische Chemie, Hochschule Aalen, Beethovenstrasse 1, D-73430 Aalen, Germany
*Correspondence e-mail: willi.kantlehner@htw-aalen.de

(Received 11 June 2012; accepted 14 June 2012; online 20 June 2012)

The title compound, C12H28N6, is located about an inversion center situated at the center of the —CH2—CH2— bond. The C—N bond lengths are 1.285 (2), 1.384 (2) and 1.395 (1) Å, indicating double- and single-bond character. The N—C—N angles are 114.1 (1), 119.3 (1) and 126.5 (1)°, showing a deviation of both CN3 planes from an ideal trigonal–planar geometry.

Related literature

For the crystal structure of N,N,N′,N′-tetra­methyl­chloro­formamidinium-chloride, see: Tiritiris & Kantlehner (2008[Tiritiris, I. & Kantlehner, W. (2008). Z. Kristallogr. 223, 345-346.]). For the synthesis of N,N,N′,N′-tetra­methyl-N′′-[2-(N′,N′,N′′,N′′-tetra­methyl­guanidino)-eth­yl]-guanidine and the crystal structure of the corresponding diprotonated bis­guanidinium dichloride salt, see: Wittmann et al. (2000[Wittmann, H., Schorm, A. & Sundermeyer, J. (2000). Z. Anorg. Allg. Chem. 626, 1583-1590.]). For the synthesis and characterization of bis­guanidine–copper complexes, see: Bienemann et al. (2010[Bienemann, O., Haase, R., Flörke, U., Döring, A., Kuckling, D. & Herres-Pawlis, S. (2010). Z. Naturforsch. Teil B, 65, 798-806.]).

[Scheme 1]

Experimental

Crystal data
  • C12H28N6

  • Mr = 256.40

  • Monoclinic, P 21 /n

  • a = 8.4189 (6) Å

  • b = 8.5894 (6) Å

  • c = 11.0089 (8) Å

  • β = 106.858 (5)°

  • V = 761.88 (10) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.07 mm−1

  • T = 293 K

  • 0.22 × 0.18 × 0.15 mm

Data collection
  • Bruker–Nonius KappaCCD diffractometer

  • 7247 measured reflections

  • 1835 independent reflections

  • 1120 reflections with I > 2σ(I)

  • Rint = 0.043

Refinement
  • R[F2 > 2σ(F2)] = 0.036

  • wR(F2) = 0.096

  • S = 0.86

  • 1835 reflections

  • 87 parameters

  • H-atom parameters constrained

  • Δρmax = 0.11 e Å−3

  • Δρmin = −0.13 e Å−3

Data collection: COLLECT (Hooft, 2004[Hooft, R. W. W. (2004). COLLECT. Bruker-Nonius BV, Delft, The Netherlands.]); cell refinement: SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: DIAMOND (Brandenburg & Putz, 2005[Brandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

The synthesis of N,N,N',N'-tetramethyl-N''- [2-(N',N',N'',N''-tetramethylguanidino)-ethyl]- guanidine is well known in literature (Wittmann et al., 2000). The compound was used as a nitrogen donor ligand in reactions with copper halogenides (CuI or CuCl2), to give mono- or bis-chelate complexes (Bienemann et al., 2010). However, the crystal structure of the free guanidine base was previously unknown. According to the structure analysis, the C1–N3 bond in the bisguanidine is 1.285 (2) Å, indicating double bond character. The bond lengths C1–N2 = 1.384 (2) Å and C1–N1 = 1.395 (1) Å are elongated and characteristic for a C–N imine single bond. The N–C1–N angles are 114.1 (1)° (N1–C1–N2), 126.5 (1)° (N2–C1–N3) and 119.3 (1)° (N1–C1–N3), showing a deviation of both CN3 planes from an ideal trigonal planar geometry (Fig. 1). The dihedral angle N3—C6—C6i—N3i is 180.00 (9). The bonds between the N atoms and the terminal C-methyl groups, all have values close to a typical single bond (1.442 (2)–1.459 (1) Å). This is completely different compared with the geometrical parameters from the crystal structure analysis of the corresponding diprotonated bisguanidinium dichloride salt (Wittmann et al., 2000). Here, the C–N bond lengths of the CN3 units are in a range between 1.336 (2) and 1.342 (2) Å, the N–C–N angles are 119.5 (1), 120.1 (1) and 120.4 (1)°, indicating also delocalization of the positive charges on both CN3 planes. The crystal packing in the here presented title compound is through van der Waals interactions, only.

Related literature top

For the crystal structure of N,N,N',N'- tetramethylchloroformamidinium-chloride, see: Tiritiris & Kantlehner (2008). For the synthesis of N,N,N',N'-tetramethyl-N''-[2-(N',N',N'',N''-tetramethylguanidino)-ethyl]-guanidine and the crystal structure of the corresponding diprotonated bisguanidinium dichloride salt, see: Wittmann et al. (2000). For the synthesis and characterization of bisguanidine–copper complexes, see: Bienemann et al. (2010)

Experimental top

Two equivalents of N,N,N',N'-tetramethylchloroformamidinium-chloride (Tiritiris & Kantlehner, 2008) were reacted with one equivalent of ethane-1,2-diamine in acetonitrile in the presence of triethylamine at 273 K. The obtained protonated bisguanidinium dichloride salt was reacted in a next step with an aqueous sodium hydroxide solution at 273 K. After extraction of the bisguanidine with diethyl ether from the water phase, the solvent was evaporated and the title compound was isolated in form of a colourless solid. Single crystals have been obtained by recrystallization from a saturated acetonitrile solution.

Refinement top

The hydrogen atoms of the methyl groups were allowed to rotate with a fixed angle around the C–N bond to best fit the experimental electron density, with U(H) set to 1.5 Ueq(C) and d(C—H) = 0.96 Å. The remaining H atoms were placed in calculated positions with d(C—H) = 0.97 Å. They were included in the refinement in the riding model approximation, with U(H) set to 1.2 Ueq(C).

Structure description top

The synthesis of N,N,N',N'-tetramethyl-N''- [2-(N',N',N'',N''-tetramethylguanidino)-ethyl]- guanidine is well known in literature (Wittmann et al., 2000). The compound was used as a nitrogen donor ligand in reactions with copper halogenides (CuI or CuCl2), to give mono- or bis-chelate complexes (Bienemann et al., 2010). However, the crystal structure of the free guanidine base was previously unknown. According to the structure analysis, the C1–N3 bond in the bisguanidine is 1.285 (2) Å, indicating double bond character. The bond lengths C1–N2 = 1.384 (2) Å and C1–N1 = 1.395 (1) Å are elongated and characteristic for a C–N imine single bond. The N–C1–N angles are 114.1 (1)° (N1–C1–N2), 126.5 (1)° (N2–C1–N3) and 119.3 (1)° (N1–C1–N3), showing a deviation of both CN3 planes from an ideal trigonal planar geometry (Fig. 1). The dihedral angle N3—C6—C6i—N3i is 180.00 (9). The bonds between the N atoms and the terminal C-methyl groups, all have values close to a typical single bond (1.442 (2)–1.459 (1) Å). This is completely different compared with the geometrical parameters from the crystal structure analysis of the corresponding diprotonated bisguanidinium dichloride salt (Wittmann et al., 2000). Here, the C–N bond lengths of the CN3 units are in a range between 1.336 (2) and 1.342 (2) Å, the N–C–N angles are 119.5 (1), 120.1 (1) and 120.4 (1)°, indicating also delocalization of the positive charges on both CN3 planes. The crystal packing in the here presented title compound is through van der Waals interactions, only.

For the crystal structure of N,N,N',N'- tetramethylchloroformamidinium-chloride, see: Tiritiris & Kantlehner (2008). For the synthesis of N,N,N',N'-tetramethyl-N''-[2-(N',N',N'',N''-tetramethylguanidino)-ethyl]-guanidine and the crystal structure of the corresponding diprotonated bisguanidinium dichloride salt, see: Wittmann et al. (2000). For the synthesis and characterization of bisguanidine–copper complexes, see: Bienemann et al. (2010)

Computing details top

Data collection: COLLECT (Hooft, 2004); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The structure of the title compound with atom labels and 50% probability displacement ellipsoids.
N,N,N',N'-Tetramethyl-N''-[2- (N',N',N'',N''-tetramethylguanidino)ethyl]guanidine top
Crystal data top
C12H28N6F(000) = 284
Mr = 256.40Dx = 1.118 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 7247 reflections
a = 8.4189 (6) Åθ = 2.7–28.1°
b = 8.5894 (6) ŵ = 0.07 mm1
c = 11.0089 (8) ÅT = 293 K
β = 106.858 (5)°Polyhedral, colourless
V = 761.88 (10) Å30.22 × 0.18 × 0.15 mm
Z = 2
Data collection top
Bruker–Nonius KappaCCD
diffractometer
1120 reflections with I > 2σ(I)
Radiation source: sealed tubeRint = 0.043
Graphite monochromatorθmax = 28.1°, θmin = 2.7°
φ scans, and ω scansh = 1111
7247 measured reflectionsk = 1111
1835 independent reflectionsl = 1414
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.036H-atom parameters constrained
wR(F2) = 0.096 w = 1/[σ2(Fo2) + (0.059P)2]
where P = (Fo2 + 2Fc2)/3
S = 0.86(Δ/σ)max < 0.001
1835 reflectionsΔρmax = 0.11 e Å3
87 parametersΔρmin = 0.13 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.57 (2)
Crystal data top
C12H28N6V = 761.88 (10) Å3
Mr = 256.40Z = 2
Monoclinic, P21/nMo Kα radiation
a = 8.4189 (6) ŵ = 0.07 mm1
b = 8.5894 (6) ÅT = 293 K
c = 11.0089 (8) Å0.22 × 0.18 × 0.15 mm
β = 106.858 (5)°
Data collection top
Bruker–Nonius KappaCCD
diffractometer
1120 reflections with I > 2σ(I)
7247 measured reflectionsRint = 0.043
1835 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0360 restraints
wR(F2) = 0.096H-atom parameters constrained
S = 0.86Δρmax = 0.11 e Å3
1835 reflectionsΔρmin = 0.13 e Å3
87 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
N10.04772 (12)0.18588 (12)0.32603 (9)0.0485 (3)
N20.20678 (12)0.08543 (13)0.31899 (10)0.0556 (3)
N30.01179 (12)0.13388 (11)0.12955 (9)0.0484 (3)
C10.05014 (13)0.13573 (13)0.25085 (10)0.0434 (3)
C20.22265 (16)0.20743 (17)0.26375 (13)0.0607 (4)
H2A0.23920.30350.21730.091*
H2B0.28190.21050.32620.091*
H2C0.26310.12260.20640.091*
C30.01949 (17)0.29870 (15)0.42638 (12)0.0571 (3)
H3A0.13840.29140.45350.086*
H3B0.02280.27750.49680.086*
H3C0.01280.40170.39500.086*
C40.24173 (19)0.01111 (18)0.44203 (13)0.0688 (4)
H4A0.29720.08350.50690.103*
H4B0.31160.07780.44440.103*
H4C0.13960.02160.45630.103*
C50.35164 (16)0.12927 (18)0.28218 (14)0.0664 (4)
H5A0.31860.19140.20650.100*
H5B0.40730.03730.26630.100*
H5C0.42540.18830.34920.100*
C60.06621 (15)0.04024 (13)0.05215 (10)0.0488 (3)
H6A0.13850.03690.10490.059*
H6B0.13310.10640.01500.059*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0438 (5)0.0632 (6)0.0376 (5)0.0024 (4)0.0103 (4)0.0085 (4)
N20.0442 (5)0.0785 (7)0.0409 (6)0.0042 (5)0.0074 (4)0.0036 (5)
N30.0528 (6)0.0556 (6)0.0351 (5)0.0067 (4)0.0099 (4)0.0028 (4)
C10.0434 (6)0.0495 (6)0.0357 (6)0.0011 (4)0.0090 (5)0.0028 (4)
C20.0463 (7)0.0865 (9)0.0482 (7)0.0030 (6)0.0121 (6)0.0075 (6)
C30.0635 (8)0.0643 (8)0.0439 (7)0.0071 (6)0.0162 (6)0.0122 (5)
C40.0686 (9)0.0823 (9)0.0476 (8)0.0144 (7)0.0043 (7)0.0078 (7)
C50.0458 (7)0.0868 (10)0.0662 (9)0.0047 (6)0.0155 (7)0.0165 (7)
C60.0518 (7)0.0576 (7)0.0361 (6)0.0056 (5)0.0115 (5)0.0016 (5)
Geometric parameters (Å, º) top
N1—C11.3945 (14)C3—H3B0.9600
N1—C21.4449 (16)C3—H3C0.9600
N1—C31.4550 (15)C4—H4A0.9600
N2—C11.3837 (15)C4—H4B0.9600
N2—C51.4422 (16)C4—H4C0.9600
N2—C41.4483 (17)C5—H5A0.9600
N3—C11.2852 (15)C5—H5B0.9600
N3—C61.4589 (13)C5—H5C0.9600
C2—H2A0.9600C6—C6i1.516 (2)
C2—H2B0.9600C6—H6A0.9700
C2—H2C0.9600C6—H6B0.9700
C3—H3A0.9600
C1—N1—C2117.02 (10)H3A—C3—H3C109.5
C1—N1—C3119.32 (9)H3B—C3—H3C109.5
C2—N1—C3113.16 (10)N2—C4—H4A109.5
C1—N2—C5121.12 (11)N2—C4—H4B109.5
C1—N2—C4123.22 (10)H4A—C4—H4B109.5
C5—N2—C4114.76 (11)N2—C4—H4C109.5
C1—N3—C6119.87 (10)H4A—C4—H4C109.5
N3—C1—N2126.52 (10)H4B—C4—H4C109.5
N3—C1—N1119.28 (11)N2—C5—H5A109.5
N2—C1—N1114.14 (10)N2—C5—H5B109.5
N1—C2—H2A109.5H5A—C5—H5B109.5
N1—C2—H2B109.5N2—C5—H5C109.5
H2A—C2—H2B109.5H5A—C5—H5C109.5
N1—C2—H2C109.5H5B—C5—H5C109.5
H2A—C2—H2C109.5N3—C6—C6i109.70 (12)
H2B—C2—H2C109.5N3—C6—H6A109.7
N1—C3—H3A109.5C6i—C6—H6A109.7
N1—C3—H3B109.5N3—C6—H6B109.7
H3A—C3—H3B109.5C6i—C6—H6B109.7
N1—C3—H3C109.5H6A—C6—H6B108.2
C6—N3—C1—N215.52 (18)C2—N1—C1—N310.45 (16)
C6—N3—C1—N1161.37 (10)C3—N1—C1—N3132.01 (12)
C5—N2—C1—N346.34 (18)C2—N1—C1—N2166.81 (11)
C4—N2—C1—N3145.11 (14)C3—N1—C1—N250.74 (15)
C5—N2—C1—N1136.65 (12)C1—N3—C6—C6i138.63 (13)
C4—N2—C1—N131.90 (17)
Symmetry code: (i) x, y, z.

Experimental details

Crystal data
Chemical formulaC12H28N6
Mr256.40
Crystal system, space groupMonoclinic, P21/n
Temperature (K)293
a, b, c (Å)8.4189 (6), 8.5894 (6), 11.0089 (8)
β (°) 106.858 (5)
V3)761.88 (10)
Z2
Radiation typeMo Kα
µ (mm1)0.07
Crystal size (mm)0.22 × 0.18 × 0.15
Data collection
DiffractometerBruker–Nonius KappaCCD
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
7247, 1835, 1120
Rint0.043
(sin θ/λ)max1)0.663
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.096, 0.86
No. of reflections1835
No. of parameters87
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.11, 0.13

Computer programs: COLLECT (Hooft, 2004), SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg & Putz, 2005).

 

Acknowledgements

The authors thank Dr F. Lissner (Institut für Anorganische Chemie, Universität Stuttgart) for measuring the crystal data.

References

First citationBienemann, O., Haase, R., Flörke, U., Döring, A., Kuckling, D. & Herres-Pawlis, S. (2010). Z. Naturforsch. Teil B, 65, 798–806.  CAS Google Scholar
First citationBrandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
First citationHooft, R. W. W. (2004). COLLECT. Bruker–Nonius BV, Delft, The Netherlands.  Google Scholar
First citationOtwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationTiritiris, I. & Kantlehner, W. (2008). Z. Kristallogr. 223, 345–346.  CAS Google Scholar
First citationWittmann, H., Schorm, A. & Sundermeyer, J. (2000). Z. Anorg. Allg. Chem. 626, 1583–1590.  CrossRef CAS Google Scholar

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ISSN: 2056-9890
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